1. Field of the Invention
The present invention relates to a device configured to detect information relating to a sample by using an electromagnetic wave in the frequency band of 30 gigahertz (GHz) to 30 terahertz (THz).
2. Description of the Related Art
As a method, an apparatus, a device, etc. that are configured to generate and detect the frequency band of 30 GHz to 30 THz (hereinafter referred to as a terahertz wave) from a millimeter wave have been developed in recent years, technologies using terahertz waves receive attention. For example, the technology of performing imaging by using a safe fluoroscopic-inspection device in place of an X-ray machine, the spectroscopic technology of testing the bonding state by studying the absorption spectrum and/or complex permittivity of matter, the technology of analyzing a biomolecule, a communication technology, etc. have been studied and developed, as new application fields of the terahertz wave.
FIG. 11 is a schematic diagram of a known technology relating to “Appl. Phys. Lett. 154, Vol 80, 2002”, which is a paper on a transmission-line-type terahertz detector. As shown in FIG. 11, a transmission section is provided between a terahertz-wave-generation unit 111 and a terahertz-wave-detection unit 112, a filter unit 113 is provided in the part corresponding to the transmission section, and a solution 114 containing deoxyribonucleic acids (DNAs) is provided on the filter unit 113, where the DNA is a sample. The DNA is dropped on a transmission line, and the DNA is analyzed based on the difference between the signal of an electromagnetic wave propagated through the transmission line when the DNA is provided and the signal of an electromagnetic wave propagated through the transmission line when the DNA is not provided. That is to say, “Appl. Phys. Lett. 154, Vol 80, 2002” discloses that the difference between a single-stranded DNA and a double-stranded DNA is detected based on the difference between permittivities by using the transmission-line-type terahertz detector.
Further, Japanese Patent Laid-Open No. 2001-13087 discloses a transmission-line-type detector configured to calculate the water content of an object to be measured including soil, a solution, etc. An output end is divided into branches by using a microwave, and transmission lines with different lengths are provided. According to Japanese Patent Laid-Open No. 2001-13087, any of the transmission lines is selected in consideration of the propagation loss of an electromagnetic wave, and high to low degrees of water contents are calculated.